Large-scale analysis of dielectric and mechanical properties of pavement using GPR and LFWD

Over the last few years ground-penetrating radar (GPR) has proved to be an effective instrument for pavement applications spanning from physical to geometrical inspections of roads. In this paper, the new challenge of inferring mechanical properties of road pavements and materials from their dielectric characteristics was investigated. A pulsed GPR system with ground-coupled antennas, 600 MHz and 1600 MHz center frequencies of investigation, was used over a 4 m×30 m test site with a flexible pavement structure. A spacing of 0.40 m between the GPR acquisition tracks was considered both longitudinally and transversely in order to configure a square regular grid mesh of 836 nodes. Accordingly, the Young's modulus of elasticity was measured on each grid node using light falling weight deflectometer (LFWD). Therefore, a semi-empirical model for predicting strength properties of pavement was developed by comparing the observed elastic modulus and the electromagnetic response of substructure on each grid node. A good agreement between observed and modeled values was found, thereby showing great promises for large-scale mechanical inspections of pavements using GPR.